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McCulloch Mc 90,91,92,93 Identification
Posted: Wed Jan 06, 2010 5:05 am
by Bill Legere
How do I identify the differences in these engines? Are the completely interchangeable? I have 4 engines of this style, 2 are marked, 2 are not.
Re: McCulloch Mc 90,91,92,93 Identification
Posted: Wed Jan 06, 2010 7:54 am
by Rob Voska
Ports, cranks and PTO bearings are the big differences. Most parts interchange.
Re: McCulloch Mc 90,91,92,93 Identification
Posted: Wed Jan 06, 2010 11:43 pm
by Scott Kneisel
To further clarify,
All the Mc91's have a needle bearing on the PTO side. This can be identified by a very small OD seal on the PTO. There are differences in porting between the 91's and the Mc91B1 also has a thicker top fin on the block
The Mc92 and Mc93 have a ball bearing on the PTO and the external PTO seal has a muck larger diameter similar to the Mc101.
The Mc92 has a recessed copper head gasket and a recessed exhaust manifold gasket. The Mc93 went back to the standard aluminum head gasked and a flat flange on the exhaust ports. Pistons, rods, heads, ignition, stuffers, side cover, carbs & manifolds, flywheel and flywheel cover are all basically the same and interchangeable on all the 91 series.
Good luck,
Scott